A burgeoning counter-drone industry has emerged, with some 300 products on the market including nets, lasers and radars that jam a drone’s GPS signal. Police in the Netherlands have even trained eagles to catch drones.
But drone technology is also developing so fast that countermeasures can quickly be made obsolete.
"As they come up with new technologies, we are going to have to counter the new technologies," Bennett said. "It's a never-ending circle of events."
Richard Engel reported from Washington, and Kennett Werner from London.
Richard Engel has been NBC News' chief foreign correspondent since 2008.